14
J A C K C O H E N
FIG. 6. Transverse sections of a growing Brown Leghorn capon breast feather in
its follicle. Compare to Fig. 3.
A. The dermal papilla with the follicle wall reflecting onto its surface on its
dorsal aspect. The epithelium comes a trifle lower (about 30 μ) on the dorsal
aspect than on the ventral. The series is also not perfectly transverse (see below).
X 36.
B. The papilla sectioned somewhat below the collar. This series has been stained
in Alcian Blue, Weigert hematoxylin, and Ponceau S, and photographed in blue
light. The light crescent to the right (dorsal) in the dermal papilla is stained with
Alcian Blue and probably represents the "active" part of the papilla, with high
concentration of mucopolysaccharides. The slight tilt of the sections makes this
more obvious than it should be; however, it is most probably not simply the
proximal end of the pulp, which is also positive to Alcian Blue, though not as
strongly. The right edge of this section is about 25 μ higher than the left. X 36.
C. Above the collar region (in which the widening of the feather cylinder makes
interpretation difficult) barb ridges and the rachis can be seen clearly. Also note
the feather sheath (crinkled) and the real follicular cavity. X 36.
D. About 2 mm higher still. The barb ridges have become pairs of barbules
attached to barbs (compare Fig. 4B). Also note the large arrector muscles in
oblique section. X 30.
J A C K C O H E N
FIG. 6. Transverse sections of a growing Brown Leghorn capon breast feather in
its follicle. Compare to Fig. 3.
A. The dermal papilla with the follicle wall reflecting onto its surface on its
dorsal aspect. The epithelium comes a trifle lower (about 30 μ) on the dorsal
aspect than on the ventral. The series is also not perfectly transverse (see below).
X 36.
B. The papilla sectioned somewhat below the collar. This series has been stained
in Alcian Blue, Weigert hematoxylin, and Ponceau S, and photographed in blue
light. The light crescent to the right (dorsal) in the dermal papilla is stained with
Alcian Blue and probably represents the "active" part of the papilla, with high
concentration of mucopolysaccharides. The slight tilt of the sections makes this
more obvious than it should be; however, it is most probably not simply the
proximal end of the pulp, which is also positive to Alcian Blue, though not as
strongly. The right edge of this section is about 25 μ higher than the left. X 36.
C. Above the collar region (in which the widening of the feather cylinder makes
interpretation difficult) barb ridges and the rachis can be seen clearly. Also note
the feather sheath (crinkled) and the real follicular cavity. X 36.
D. About 2 mm higher still. The barb ridges have become pairs of barbules
attached to barbs (compare Fig. 4B). Also note the large arrector muscles in
oblique section. X 30.